Vacuum cleaner

ABSTRACT

A vacuum cleaner includes: a vacuum motor; one or more time of flight sensors configured to generate first sensor signals dependent on the proximity of an object to the one or more time of flight sensors; a capacitive sensor located in proximity to a handle of the vacuum cleaner and configured to generate second sensor signals dependent on whether a user is gripping the handle; and a controller configured to: process the generated first and second sensor signals to determine whether the vacuum cleaner is actively being used by the user; and in response to determining that the vacuum cleaner is actively being used, activate the vacuum motor.

TECHNICAL FIELD

The present disclosure relates to a vacuum cleaner. In particular, butnot exclusively, the present disclosure concerns measures, includingmethods, apparatus and computer programs, for operating a vacuumcleaner.

BACKGROUND

Broadly speaking, there are four types of vacuum cleaner: ‘upright’vacuum cleaners, ‘cylinder’ vacuum cleaners (also referred to as‘canister’ vacuum cleaners), ‘handheld’ vacuum cleaners and ‘stick’vacuum cleaners.

Upright vacuum cleaners and cylinder vacuum cleaners tend to bemains-power-operated.

Handheld vacuum cleaners are relatively small, highly portable vacuumcleaners, suited particularly to relatively low duty applications suchas spot cleaning floors and upholstery in the home, interior cleaning ofcars and boats etc. Unlike upright cleaners and cylinder cleaners, theyare designed to be carried in the hand during use, and tend to bepowered by battery.

Stick vacuum cleaners may comprise a handheld vacuum cleaner incombination with a rigid, elongate suction wand which effectivelyreaches down to the floor so that the user may remain standing whilecleaning a floor surface. A floor tool is typically attached to the endof the rigid, elongate suction wand, or alternatively may be integratedwith the bottom end of the wand.

Stick vacuum cleaners are typically operated by depressing a physicaltrigger switch, which causes the vacuum motor to activate. When thetrigger switch is released, the vacuum motor is usually immediatelydeactivated. This has the benefit that the battery is not unnecessarilydepleted, since the user is inclined to release the trigger whenpossible, for example when moving between different areas. Nevertheless,extended cleaning sessions in which the user is required to keep aphysical trigger switch depressed can result in some mild discomfort forsome users.

It is an object of the present disclosure to mitigate or obviate theabove disadvantages, and/or to provide an improved or alternative vacuumcleaner.

SUMMARY

According to an aspect of the present disclosure, there is provided avacuum cleaner comprising: a vacuum motor; one or more time of flightsensors configured to generate first sensor signals dependent on theproximity of an object to the one or more time of flight sensors; acapacitive sensor located in proximity to a handle of the vacuum cleanerand configured to generate second sensor signals dependent on whether auser is gripping the handle; and a controller configured to: process thegenerated first and second sensor signals to determine whether thevacuum cleaner is actively being used by the user; and in response todetermining that the vacuum cleaner is actively being used, activate thevacuum motor.

Advantageously, the controller activates the vacuum motor when itdetermines, from the capacitive sensor and the one or more time offlight sensors, that the user is actively using the vacuum cleaner. Inthis manner, when the user is gripping the handle and manoeuvres thevacuum cleaner so as to approach an object or surface to be cleaned, thecontroller will automatically activate the vacuum motor without the userbeing required to depress a physical trigger switch. This results inimproved user comfort and convenience.

In embodiments, the controller is further configured to deactivate thevacuum motor in response to determining that the vacuum cleaner is nolonger actively being used by the user.

In embodiments, the controller is configured to process the first andsecond sensor signals to determine whether the vacuum cleaner isactively being used both when the vacuum motor is activated and when thevacuum motor is deactivated.

In embodiments, the one or more time of flight sensors comprise a radardevice and/or a laser device.

In embodiments, determining that the vacuum cleaner is actively beingused comprises determining, from the first sensor signals, that theobject is within a predetermined threshold distance from at least one ofthe one or more time of flight sensors.

In embodiments, the vacuum cleaner further comprises one or moredetachable tools, wherein the predetermined threshold distance isdependent on the type of detachable tool attached to the vacuum cleaner.This may be desirable to tailor the response of the vacuum cleaner todifferent cleaning scenarios. For example, when using a dusting brush,the pre-determined threshold distance may be less than when using thecrevice tool, since the vacuum motor is only required to activate whendusting brush is actually resting on the surface being cleaned, forexample. This helps to conserve battery power, since the vacuum motor isnot activated prematurely.

In embodiments, each of the one or more detachable tools comprises oneof the one or more time of flight sensors.

In embodiments, the one or more detachable tools comprise one or moreof: a crevice tool, a dusting brush, and a miniature motorized tool.

In embodiments, the vacuum cleaner further comprises a detachable wand,the detachable wand comprising one of the one or more time of flightsensors.

In embodiments, one of the one or more time of flight sensors is locatedon a main body of the vacuum cleaner.

In embodiments, determining that the vacuum cleaner is actively beingused comprises determining, from the second sensor signals, that theuser is gripping the handle of the vacuum cleaner.

In embodiments, the controller is configured to process the sensorsignals by performing a pre-processing step and a classification step.

In embodiments, the pre-processing step comprises extracting featuresfrom time portions of the sensor signals.

In embodiments, the pre-processing step comprises filtering the sensorsignals.

In embodiments, the classification step comprises processing theextracted features using a machine learning classifier. Advantageously,a machine learning classifier can be pre-trained, for example at thefactory, by subjecting the vacuum cleaner to a multitude of differentcleaning activities/scenarios and defining how the vacuum cleaner shouldrespond in each case. Furthermore, the machine learning classifier maybe capable of further learning in the user's home environment.

In embodiments, the machine learning classifier comprises one or moreof: an artificial neural network, a random forest and a support-vectormachine.

According to an aspect of the present disclosure, there is provided amethod of operating a vacuum cleaner comprising: generating first sensorsignals by one or more time of flight sensors, the first sensor signalsdependent on the proximity of an object to the one or more time offlight sensors; generating second sensor signals by a capacitive sensorlocated in proximity to a handle of the vacuum cleaner, the secondsensor signals dependent on whether a user gripping the handle;processing the first and second sensor signals to determine whether thevacuum cleaner is actively being used by the user; and in response todetermining that the vacuum cleaner is actively being used, activating avacuum motor of the vacuum cleaner.

According to an aspect of the present disclosure, there is provided acomputer program comprising a set of instructions, which, when executedby a computerised device, cause the computerised device to perform amethod of operating a vacuum cleaner, the method comprising: generatingfirst sensor signals by one or more time of flight sensors, the firstsensor signals dependent on the proximity of an object to the one ormore time of flight sensors; generating second sensor signals by acapacitive sensor located in proximity to a handle of the vacuumcleaner, the second sensor signals dependent on whether a user grippingthe handle; processing the first and second sensor signals to determinewhether the vacuum cleaner is actively being used by the user; and inresponse to determining that the vacuum cleaner is actively being used,activating a vacuum motor of the vacuum cleaner.

The present disclosure is not limited to any particular type of vacuumcleaner. For example, the aspects of the disclosure may be utilised onupright vacuum cleaners, cylinder vacuum cleaners or handheld or ‘stick’vacuum cleaners.

It should be appreciated that features described in relation to oneaspect of the present disclosure may be incorporated into other aspectsof the present disclosure. For example, a method aspect may incorporateany of the features described with reference to an apparatus aspect andvice versa.

DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described by way ofexample only with reference to the accompanying schematic drawings ofwhich:

FIG. 1 is a perspective view of a stick vacuum cleaner according to anembodiment of the present disclosure;

FIG. 2 is a view of a cleaner head of the vacuum cleaner of FIG. 1 ,shown from underneath;

FIG. 3 is a schematic illustration of electrical components of thevacuum cleaner of FIG. 1 ;

FIG. 4 is a perspective view of a main body of the stick vacuum cleanerof FIG. 1 ;

FIGS. 5 a and 5 b illustrate sensor signals corresponding to linear andangular acceleration generated by an inertial measurement unit of avacuum cleaner according to embodiments of the present disclosure;

FIGS. 6 and 7 illustrates further sensor signals corresponding toorientation generated by the inertial measurement unit of a vacuumcleaner according to embodiments of the present disclosure;

FIG. 8 is a simplified schematic illustration of electrical componentsof the vacuum cleaner of FIG. 3 , showing electrical connections betweensensors, a human-computer interface, motors and the controller accordingto embodiments of the present disclosure;

FIG. 9 is a block diagram illustrating example sensor signal processingperformed by the controller according to various embodiments of thepresent disclosure;

FIG. 10 is a flow diagram showing a method of operating a vacuum cleanerwithout a trigger according to an embodiment of the present disclosure;

FIG. 11 illustrates example sensor signal processing performed by thecontroller applicable to the method illustrated in FIG. 10 according toembodiments of the present disclosure;

FIG. 12 is a flow diagram showing a method of operating a vacuum cleanerbased on a latching trigger according to embodiments of the presentdisclosure;

FIG. 13 is a flow diagram showing a method of operating a vacuum cleanerbased on a time of flight sensor and a capacitive sensor according toembodiments of the present disclosure;

FIGS. 14 a and 14 b illustrates an example cleaning activity applicableto the method illustrated in FIG. 13 according to embodiments of thepresent disclosure;

FIG. 15 is a flow diagram showing a method of operating a vacuum cleanerbased on a motion and orientation sensor and parameters of a cleanerhead according to embodiments of the present disclosure; and

FIGS. 16 a and 16 b illustrate an example cleaning activity applicableto the method illustrated in FIG. 15 according to embodiments of thepresent disclosure.

DETAILED DESCRIPTION

FIGS. 1 to 4 illustrate a vacuum cleaner 2 according to embodiments ofthe present disclosure. The vacuum cleaner 2 is a ‘stick’ vacuum cleanercomprising a cleaner head 4 connected to a main body 6 by a generallytubular elongate wand 8. The cleaner head 4 is also connectable directlyto the main body 6 to transform the vacuum cleaner 2 into a handheldvacuum cleaner. Other removable tools, such as a crevice tool 3, adusting brush 7 and a miniature motorized cleaner head 5 may be attacheddirectly to the main body 6, or to the end of the elongate wand 8, tosuit different cleaning tasks.

The main body 6 comprises a dirt separator 10 which in this case is acyclonic separator. The cyclonic separator has a first cyclone stage 12comprising a single cyclone, and a second cyclone stage 14 comprising aplurality of cyclones 16 arranged in parallel. The main body 6 also hasa removable filter assembly 18 provided with vents 20 through which aircan be exhausted from the vacuum cleaner 2. The main body 6 of thevacuum cleaner 2 has a pistol grip 22 positioned to be held by the user.At an upper end of the pistol grip 22 is a user input device in the formof a trigger switch 24, which is usually depressed in order to switch onthe vacuum cleaner 2. However, in some embodiments the physical triggerswitch 24 is optional. Positioned beneath a lower end of the pistol grip22 is a battery pack 26 which comprises a plurality of rechargeablecells 27. A controller 50 and a vacuum motor 52, comprising a fan drivenby an electric motor, are provided in the main body 6 behind the dirtseparator 10.

The cleaner head 4 is shown from underneath in FIG. 2 . The cleaner head4 has a casing which defines a suction chamber 32 and a soleplate 34.The soleplate 34 has a suction opening 36 through which air can enterthe suction chamber 32, and wheels 37 for engaging a floor surface. Thecasing 30 defines an outlet 38 through which air can pass from thesuction chamber 32 into the wand 8. Positioned inside the suctionchamber 32 is an agitator 40 in the form of a brush bar. The agitator 40can be driven to rotate inside the suction chamber 32 by an agitatormotor 54. The agitator motor 54 of this embodiment is received insidethe agitator 40. The agitator 40 has helical arrays of bristles 43projecting from grooves 42, and is positioned in the suction chambersuch that the bristles 43 project out of the suction chamber 34 throughthe suction opening 36.

FIG. 3 is a schematic representation of the electrical components of thevacuum cleaner 2. The controller 50 manages the supply of electricalpower from the cells 27 of the battery pack 26 to the vacuum motor 52.When the vacuum motor 52 is powered on, this creates a flow of air so asto generate suction. Air with dirt entrained therein is sucked into thecleaner head 4 (or, when attached, one of the other tools such as thecrevice tool 3, the mini motorised cleaner head 5, or the dusting brush7), into the suction chamber 32 through the suction opening 36. Fromthere, the air is sucked through the outlet 38 of the cleaner head 4,along the wand 8 and into the dirt separator 10. Entrained dirt isremoved by the dirt separator 10 and then relatively clean air is drawnthrough the vacuum motor 52, through the filter assembly 18 and out ofthe vacuum cleaner 2 through the vents 20. In addition, the controller50 also supplies electrical power from the battery pack 26 to theagitator motor 54 of the cleaner head 4, through wires 56 running alongthe inside of the wand, so as to rotate the agitator 40. When thecleaner head 4 is on a hard floor, it is supported by the wheels 37 andthe soleplate 34 and agitator 40 are spaced apart from the floorsurface. When the cleaner head 4 is resting on a carpeted surface, thewheels 37 sink into the pile of the carpet and the soleplate 34 (alongwith the rest of the cleaner head 4) is therefore positioned furtherdown. This allows carpet fibres to protrude towards (and potentiallythrough) the suction opening 36, whereupon they are disturbed bybristles 43 of the rotating agitator 40 so as to loosen dirt and dusttherefrom.

Vacuum cleaners 2 according to embodiments of the present disclosurecomprise additional components, which are visible in FIGS. 3 and 4 .These include one or more of: a current sensor 58 for sensing theelectrical current drawn by the agitator motor 54 of the cleaner head 4,a pressure sensor 60 for sensing the pressure applied to the soleplate34 of the cleaner head 4, an inertial measurement unit (IMU) 62 which issensitive to motion and orientation of the main body 6 of the vacuumcleaner 2, a human computer interface (HCl) 64, one or more proximitysensors, typically in the form of time of flight (TOF) sensors 72, atool switch sensor 74 and a capacitive sensor 76 located in the pistolgrip 22. Although the current sensor 58 is shown as being situated inthe cleaner head 4, it could alternatively be located in the main body6. For example, the current sensor 58 could be integrated as part of thecontroller 50, provided it is operable to sense electrical currentsupplied to the agitator motor 54 from the battery 26 via the wires 56.In the illustrated embodiment, one TOF sensor 72 is located at the endof the detachable wand 8, close to where the cleaner head 4, or one ofthe other tools 3, 5, 7, is attached. Further TOF sensors 72 may beprovided on the removable tools 3, 5, 7 themselves. Each TOF sensor 72generates a sensor signal dependent on the proximity of objects to theTOF sensor 72. Suitable TOF sensors 72 include radar or laser devices.The tool switch sensor 74 is located on the main body 6 of the vacuumcleaner 2 and generates signals dependent on whether a tool 3, 4, 5, 7or the wand 8 is attached to the main body 6. In embodiments, the toolswitch sensor 74 generates signals dependent on the type of tool 3, 4,5, 7 attached to main body 6 or the wand 8. The capacitive sensor 76 islocated in the pistol grip 22 and generates signals dependent on whethera user is gripping the pistol grip. In embodiments, the vacuum cleaner 2may comprise one or more additional IMUs. For example, the cleaner head4 may comprise an IMU which is sensitive to motion and orientation ofthe cleaner head 4 and which generates further sensor signals tosupplement those generated by the IMU 62 of the main body 6. The IMU 62may comprise one or more accelerometers, one or more gyroscopes and/orone or more magnetometers.

As shown in more detail in FIG. 4 , the main body 6 of the vacuumcleaner 2 defines a longitudinal axis 70 which runs from a front end 9to a rear end 11 of the main body 6. When it is attached to the frontend 9 of the main body 6, the wand 8 is parallel to (and in this casecollinear with) the longitudinal axis 70. In the illustrated embodiment,the HCl 64 comprises a visual display unit 65, more particularly aplanar, full colour, backlit thin-film transistor (TFT) screen. Thescreen 65 is controlled by the controller 50 and receives power from thebattery 26. The screen displays information to the user, such as anerror message, an indication of a mode the vacuum cleaner 2 is operatingin, or an indication of remaining battery 26 life. The screen 65 facessubstantially rearwards (i.e. its plane is orientated substantiallynormal to the longitudinal axis 70). Positioned beneath the screen 65(in the vertical direction defined by the pistol grip 22) is a pair ofcontrol members 66, also forming part of the HCl 64 and each of which ispositioned adjacent to the screen 65 and is configured to receive acontrol input from the user. In embodiments, the control members areconfigured to change the mode of the vacuum cleaner, for example tomanually increase or decrease the power of the vacuum motor 52. Inembodiments, the HCl 64 also comprises an audio output device such as aspeaker 67 which can provide audible feedback to the user.

The IMU 62 generates sensor signals dependent on the motion andorientation of the main body 6 of the vacuum cleaner 2 in three spatialdimensions (x, y, and z). The motion includes the linear accelerationand angular acceleration of the main body 6. FIG. 5 a illustratesexemplary generated IMU 62 sensor data corresponding to the linearacceleration of the main body 6 before, during and after a cleaningoperation. The time scale shows the index of samples which were gatheredat a sampling rate of 25 Hz. The vertical scale is in units ofacceleration due to gravity. Traces 91 a, 91 b and 91 c correspond tothe linear acceleration of the main body 6 in the x, y and z directionsrespectively. FIG. 5 b illustrates exemplary generated IMU 62 sensordata corresponding to the angular acceleration of the main body 6before, during and after the same cleaning operation as represented inFIG. 5 a . Traces 92 a, 92 b and 92 c correspond to the angularacceleration about the x, y and z axes respectively. In both FIGS. 5 aand 5 b , the vacuum cleaner 2 is initially static (at rest). This isfollowed by a cleaning session comprising cleaning strokes, giving riseto oscillatory behaviour in some of the generated sensor data. Finally,the vacuum cleaner 2 is again returned to rest. The data shown in FIGS.5 a and 5 b have been smoothed, for example by means of a band-passfilter or a low-pass filter. FIG. 6 illustrates example generated IMU 62sensor data corresponding to of the orientation of the main body 6 aboutthe y axis during different hand-held cleaning operations. Specifically,interval 93 a corresponds to cleaning of a low-level surface, e.g. askirting board, interval 93 b corresponds to a period during which themain body 6 is at rest on a table and interval 93 c corresponds tocleaning of an elevated surface, for example a ceiling, blind, curtain,or the top of a cupboard. FIG. 7 illustrates further exemplary generatedIMU 62 sensor data corresponding to orientation of the main body 6 aboutthe y axis during different cleaning operations using the motorizedcleaner heads 4, 5. Trace 94 a corresponds to cleaning under furnitureusing the main cleaner head 4 attached to the wand 8. Trace 94 bcorresponds to stair cleaning using the miniature motorized cleaner head5 attached directly to the main body 6, without using the wand 8. Trace94 c corresponds to normal upright vacuum cleaning using the cleanerhead 4 attached to the wand 8. It should be appreciated that thedifferent cleaning activities give rise to different signatures in thesensor data generated by the IMU 62. In this manner, it should beappreciated that the IMU 62 sensor data can be processed to inferinformation about the cleaning activity being performed by a user usingthe vacuum cleaner, or about the environment in which the vacuum cleaneris being operated.

FIG. 8 illustrates schematically the electrical layout of the vacuumcleaner 2 according to embodiments. In embodiments, the controller 50receives and processes signals generated by one or more of the trigger24, the current sensor 58, the pressure sensor 60, the IMU 62, the oneor more TOF sensors 72, the tool switch sensor 74 and the capacitivesensor 76. The controller 50 has a memory 51 on which are storedinstructions according to which the controller 50 processes the sensorsignals. Based on the processing of the sensor signals, the controller50 controls one or more of the vacuum motor 52, the agitator motor 54and the HCl 64 in order to enhance operation of the vacuum cleaner 2 andthereby improve the user experience. Example enhancements includeimproved pickup of dirt and improved battery life, amongst others.

FIG. 9 is a block diagram which illustrates example sensor signalprocessing performed by the controller 50 according to variousembodiments of the present disclosure. Unfiltered sensor signals 88 arereceived at the controller 50 from one or more of the available sensors.Different embodiments utilize sensor signals from different sensors.Some embodiments utilize sensor signals from only one sensor, such asthe IMU 62, for example. A band-pass filter or low-pass filter 82filters the raw sensor signals 88 to generate smoothed sensor signals 90which are more suitable for further processing. At block 84,pre-determined features F₁, F₂ . . . F_(n) are extracted from thesmoothed sensor signals and subsequently analysed by a classifier 86. Inembodiments, the classifier 86 determines, from the extracted features,a particular cleaning activity being performed by a user using thevacuum cleaner 2. In other embodiments, the classifier 86 determines,from the extracted features a particular surface type on which thevacuum cleaner 2 is being operated. In other embodiments, the classifier86 determines, from the extracted features, whether the vacuum cleaner 2is actively being used, to assist in providing a trigger-less vacuumcleaner 2. Having determined the above, the controller 50 causes anaction or actions to be performed involving one or more of the vacuummotor 52, agitator motor 54 and HCl 64, which are configured independence on the classifier 86 output, and optionally on the status ofthe trigger 24. It should be appreciated that the filter 82, featureextraction block 84 and classifier 86 are in general implemented assoftware modules which are executed on or under the control of thecontroller 50. The controller memory 51 stores sets of instructionsdefining the operation of the filter 82, feature extraction 84,classifier 86 and resultant action. In embodiments, the classifier isbased on a machine learning classifier such as an artificial neuralnetwork, a random forest, a support-vector machine or any otherappropriate trained model. The model could have been pre-trained, forexample at the factory, using a supervised learning approach. A slidingwindow approach is generally used to span the filtered sensor signalsand extract features corresponding to that particular time portion ofthe signal. Consecutive frames usually overlap to some degree but areusually processed separately. It should be appreciated that it is notalways necessary to receive and process sensor data from all of theavailable sensors. For example, in embodiments the controller 50 mayprocess only IMU 62 sensor data to obtain a classifier output.Furthermore, in the case of IMU 62 sensor data, the controller 50 mayfor example take account only of IMU 62 sensor data relating toorientation of the vacuum cleaner 2, or only IMU 62 sensor data relatingto acceleration of the vacuum cleaner 2.

Although the vacuum cleaner 2 illustrated in FIGS. 1 to 4 includes aphysical trigger 24 generally used to activate the vacuum motor 52 whenthe trigger 24 is depressed, it has been appreciated that for reasons ofuser comfort it is desirable to relax the requirement to keep thetrigger 24 depressed during a vacuum cleaning operation. Indeed, some ofthe embodiments described below enable the vacuum cleaner 2 to beoperated without depressing the trigger 24 at all. Accordingly, inembodiments, the provision of a physical trigger 24 may be optional,such that it can be entirely omitted from the vacuum cleaner 2.

FIG. 10 is a flow diagram showing a method 230 of operating a vacuumcleaner 2 according to embodiments. In step 232, sensor signals aregenerated by a plurality of different sensors of the vacuum cleaner.These could include any combination of the IMU 62, the TOF sensors 72,the current sensor 58, the pressure sensor 60, the capacitive sensor 76and the tool switch sensor 74. In step 234, a first module of thecontroller 50 processes the generated sensor signals to generate aplurality of control signals. In step 236, a second module of thecontroller 50 processes the plurality of control signals to generate anoutput signal indicating that the vacuum cleaner 2 is currently beingused. In step 238, the vacuum motor 52 is activated or deactivated independence on the output signal.

With reference to FIG. 11 , the first module 100 receives sensor signalsgenerated by the various sensors available on the vacuum cleaner 2. Itshould be appreciated that at times, not all sensors are necessarilypresent, i.e. installed on the device For example, in embodiments wherethe current sensor 58 and the pressure sensor 60 are located on orwithin the detachable cleaner head 4, but the vacuum cleaner 2 is beingoperated in conjunction with the crevice tool 7, instead of with thecleaner head 4, the current sensor 58 and the pressure sensor 60 are notat that time present. However, the general architecture set out in FIG.11 is flexible in terms of adding or removing sensors providing signalsto the first module 100. The first module 100 periodically generates(e.g. once per second) a plurality of control signals 101 based on theprocessing of the generated sensor signals. For example, control signal“ctrl_detectedHAND” is indicative of whether or not a user is grippingthe handle (pistol grip 22) of the vacuum cleaner 2 as sensed forexample by the capacitive sensor 76. Control signal “ctrl_toolType” isindicative of the type of tool 3, 4, 5, 7 attached to the main body 6 orwand 8, as sensed by the tool switch sensor 74. Control signal“ctrl_cleaningShortTool” is indicative of whether the user ismaneuvering the vacuum cleaner 2 in a manner indicative of a cleaningoperation using a tool attached directly to the main body 6. Controlsignal “ctrl_cleaningLongTool” is indicative of whether the user ismaneuvering the vacuum cleaner in a manner indicative of a cleaningoperation using a tool attached to the wand 8. The processing ofgenerated sensor signals performed by the first module 100 is, inembodiments, based on the approach described above with reference toFIG. 9 . Specifically, in embodiments, the first module 100 isconfigured to process the generated sensor signals by performing apre-processing step (filtering and feature extraction) and aclassification step (based on a machine learning classifier). In thisregard, the classifier 86 is configured to provide the plurality ofcontrol signals 101.

The plurality of control signals are analysed by the second module 102which produces an output signal 103 in dependence on the control signals101. The vacuum motor 52 is activated or deactivated depending on thevalue of the output signal 103. In embodiments, the output signal is abinary signal which switches the vacuum motor 52 on and off at aninitial default power level. In other embodiments, the output signal maytake one of several values, allowing the vacuum motor 52 to be switchedon at different initial power levels (e.g. low, medium and high)depending on the plurality of control signals 101. An appropriatearchitecture for the second module 102 is a finite state machine, wherethe different states correspond to states (power levels or on/offstatus) of the vacuum motor 52. It should be appreciated that the first100 and second 102 modules may be implemented as separate softwaremodules or a single software module executed by the single controller50. The provision of first 100 and second 102 modules at differentstages in the signal processing chain, set out in FIG. 11 , enablesindependent development of the two modules. For example, changes to theway in which the classifier operates in the first module 100 do notnecessarily impact upon the operation of the second module 102 providedthe output control signals 101 adopt a consistent format. It should beappreciated that the general architecture described with reference toFIGS. 10 and 11 may form the basis for a trigger-less vacuum cleaner 2according to embodiments of the present disclosure.

FIG. 12 is a flow diagram showing a method 240 of operating a vacuumcleaner 2 according to embodiments. In step 242, the vacuum motor 52 isactivated (i.e. switched on) in response to activation of a user inputdevice by a user. In step 244, sensor signals are generated based onsensed motion and orientation of the vacuum cleaner. In step 246, thegenerated sensor signals are processed by the controller 50 to determinewhether the vacuum cleaner 2 is actively being used by the user. In step248, in response to determining that the vacuum cleaner 2 is activelybeing used, the vacuum motor 52 is retained in an activated state. Theuser input device is typically the trigger 24, such that activation ofthe user input device involves depressing the trigger 24. However,unlike conventional triggered devices, the user does not necessarilyneed to keep the trigger 24 depressed continuously during a vacuumcleaning session. This is because the vacuum motor 52 is retained in anactivated state provided the controller 50 determines that the vacuumcleaner 2 is actively being used by the user. As such, the vacuumcleaner 2 can be switched on by momentarily depressing the trigger 24,for example for a duration of less than half a second. Once switched on,the trigger 24 can be released, which improves user comfort. Therefore,the trigger effectively ‘latches’ (in a non-mechanical sense). Thecapacitive sensor 76 located in the pistol grip 22 may form part or allof the user input device. For example, instead of a physical trigger 24,the action of the capacitive sensor 76 detecting a user's hand may causeactivation of the vacuum motor 52.

In embodiments, determining that the vacuum cleaner is actively beingused by the user comprises determining that the user is holding and/ormaneuvering the vacuum cleaner in a manner indicative of a vacuumcleaning operation. In this regard, the controller 50 processes sensorsignals, such as those produced by the IMU 62, in the manner describedabove with reference to FIG. 9 . If the controller 50 determines thatthe vacuum cleaner is no longer actively being used, for example when itis set down on a table, the controller 50 deactivates the vacuum motor52 in order to conserve battery power. The controller 50 will generallywait for a pre-determined period of time (e.g. 0.5 to 5 seconds) beforedeactivating the vacuum motor 52 to avoid the vacuum motor 52 switchingoff when the device is stationary only momentarily. If no movement isdetected during this pre-determined period then the vacuum motor 52 isdeactivated. Once deactivated, the user is generally required to‘re-latch’ the vacuum cleaner 2, for example by briefly depressing thetrigger 24, before the vacuum motor 52 can be reactivated. In otherwords, merely moving the vacuum cleaner 2 around will not, inembodiments, cause the vacuum motor 52 to reactivate once it has beendeactivated following a period of inactivity. Additional sensor readingsmay be taken to determine whether the user is actively using the vacuumcleaner. Examples include readings from the current sensor 58 and thepressure sensor 60 which sense parameters of the cleaner head 4.

FIG. 13 is a flow diagram showing a method 250 of operating a vacuumcleaner 2 according to embodiments. In step 252, first sensor signalsare generated by the one or more TOF sensors 72. The first sensorsignals are dependent on the proximity of an object to the one or moreTOF sensors 72. In step 254, second sensor signals are generated by thecapacitive sensor 76, which are dependent on whether a user is grippingthe handle 22 of the vacuum cleaner. In step 256, the first and secondsensor signals are processed by the controller 50 to determine whetherthe vacuum cleaner 2 is actively being used by the user. In step 258, inresponse to determining that the vacuum cleaner 2 is actively beingused, the vacuum motor 52 is activated. The controller 50 processessensor signals in the manner described above with reference to FIG. 9 .

FIGS. 14 a and 14 b illustrate an example scenario in which a TOF sensor72 and a capacitive sensor 76 are used to trigger the vacuum cleaner 2.In this example, a crevice tool 3 comprising a TOF sensor 72 is attacheddirectly to the main body 6. The user desires to clean some dirt 96 froma crevice 97 b formed between the floor 98 a and the wall 98 c. In FIG.14 a , the user's hand (not shown) is gripping the pistol grip 22 of themain body 6, which is detected by the capacitive sensor 76 located inthe handle 22. The TOF sensor 72 may be a radar device or a laser devicewhich emits and receives electromagnetic or acoustic radiation 73 inorder to determine the proximity of objects and surfaces. In FIG. 14 a ,the TOF sensor 72 detects that the object, in this case the crevice 97b, is further away than a pre-determined threshold distance. Thereforethe vacuum motor 52 is not yet activated and remains switched off, thusconserving battery power. In FIG. 14 b , the user has moved the vacuumcleaner 2 closer to the crevice 97 b, bringing it within apre-determined threshold distance from the TOF sensor 72. Accordingly,the controller 50 determines that the vacuum cleaner 2 is actively beingused and activates the vacuum motor 52 in time to effectively remove thedirt 96. When the user moves the vacuum cleaner 2 away from the crevice97 b, this is detected by the TOF sensor 72 and the vacuum motor 52 isdeactivated. Accordingly, the vacuum cleaner 2 is activated anddeactivated as required without the user having to depress a physicaltrigger 24. When the vacuum cleaner 2 is stored, the user's hand willnot be gripping the handle 22, and therefore the vacuum motor 52 willnot activate even if objects are within the pre-determined distance fromthe TOF sensor 72. In embodiments, the predetermined threshold distanceis dependent on the type of detachable tool attached to the vacuumcleaner 2. This may be desirable to tailor the response of the vacuumcleaner 2 to different cleaning scenarios. For example, when using adusting brush 7, the pre-determined threshold distance may be less thanwhen using the crevice tool 3, since the vacuum motor 52 is onlyrequired to activate when dusting brush 7 is actually resting on thesurface being cleaned.

FIG. 15 is a flow diagram showing a method 260 of operating a vacuumcleaner 2 having a cleaner head 4 according to embodiments. In step 262,first sensor signals are generated based on sensed motion andorientation of the vacuum cleaner. The first sensor signals may begenerated by the IMU 62, for example. In step 264, second sensor signalsare generated based on sensed parameters of the cleaner head 4. Thesecond sensor signals may be generated by the current sensor 58 and/orthe pressure sensor 60. In step 266, the first and second sensor signalsare processed by the controller 50 to determine whether the vacuumcleaner 2 is actively being used by the user. In step 268, in responseto determining that the vacuum cleaner 2 is actively being used, thevacuum motor 52 is activated. The controller 50 processes sensor signalsin the manner described above with reference to FIG. 9 .

FIGS. 16 a and 16 b illustrate an example scenario in which the firstand second sensor signals are used to trigger operation of the vacuumcleaner 2. In FIG. 16 a the vacuum cleaner 2 is at rest within a dock 99mounted to the wall 98 c. The cleaner head 4 is attached to the wand 8which in turn is attached to the main body 6. The pressure applied tothe cleaner head 4 is small or zero when the vacuum cleaner 2 issuspended in the dock 99 in this manner. Furthermore, the IMU 62 willsense that the vacuum cleaner 2 is not undergoing any motion and remainsin a fixed orientation. In FIG. 16 b , the vacuum cleaner 2 has beentaken out of the dock 99 by a user. The cleaner head 4 is resting on thefloor 98 a and the user begins to move the vacuum cleaner 2 forwards inorder to start cleaning the floor. The controller 50 processes thesensor signals from the IMU 62 and the diagnostic sensors 58, 60associated with the cleaner head 4 in the manner described above withreference to FIG. 9 . This allows the controller 50 to determine thatthe user is now actively using the vacuum cleaner 2. Accordingly, thecontroller 50 activates the vacuum motor 52 without the user having todepress a trigger 24.

It is to be understood that any feature described in relation to any oneembodiment and/or aspect may be used alone, or in combination with otherfeatures described, and may also be used in combination with one or morefeatures of any other of the embodiments and/or aspects, or anycombination of any other of the embodiments and/or aspects. For example,it will be appreciated that features and/or steps described in relationto a given one of the methods 230, 240, 250, 260 may be included insteadof or in addition to features and/or steps described in relation toother ones of the methods 230, 240, 250, 260.

In embodiments of the present disclosure, the vacuum cleaner 2 comprisesa controller 50. The controller 50 is configured to perform variousmethods described herein. In embodiments, the controller comprises aprocessing system. Such a processing system may comprise one or moreprocessors and/or memory. Each device, component, or function asdescribed in relation to any of the examples described herein, forexample the IMU 62 and/or HCl 64 may similarly comprise a processor ormay be comprised in apparatus comprising a processor. One or moreaspects of the embodiments described herein comprise processes performedby apparatus. In some examples, the apparatus comprises one or moreprocessors configured to carry out these processes. In this regard,embodiments may be implemented at least in part by computer softwarestored in (non-transitory) memory and executable by the processor, or byhardware, or by a combination of tangibly stored software and hardware(and tangibly stored firmware). Embodiments also extend to computerprograms, particularly computer programs on or in a carrier, adapted forputting the above described embodiments into practice. The program maybe in the form of non-transitory source code, object code, or in anyother non-transitory form suitable for use in the implementation ofprocesses according to embodiments. The carrier may be any entity ordevice capable of carrying the program, such as a RAM, a ROM, or anoptical memory device, etc.

The one or more processors of processing systems may comprise a centralprocessing unit (CPU). The one or more processors may comprise agraphics processing unit (GPU). The one or more processors may compriseone or more of a field programmable gate array (FPGA), a programmablelogic device (PLD), or a complex programmable logic device (CPLD). Theone or more processors may comprise an application specific integratedcircuit (ASIC). It will be appreciated by the skilled person that manyother types of device, in addition to the examples provided, may be usedto provide the one or more processors. The one or more processors maycomprise multiple co-located processors or multiple disparately locatedprocessors. Operations performed by the one or more processors may becarried out by one or more of hardware, firmware, and software. It willbe appreciated that processing systems may comprise more, fewer and/ordifferent components from those described.

The techniques described herein may be implemented in software orhardware, or may be implemented using a combination of software andhardware. They may include configuring an apparatus to carry out and/orsupport any or all of techniques described herein. Although at leastsome aspects of the examples described herein with reference to thedrawings comprise computer processes performed in processing systems orprocessors, examples described herein also extend to computer programs,for example computer programs on or in a carrier, adapted for puttingthe examples into practice. The carrier may be any entity or devicecapable of carrying the program. The carrier may comprise a computerreadable storage media. Examples of tangible computer-readable storagemedia include, but are not limited to, an optical medium (e.g., CD-ROM,DVD-ROM or Blu-ray), flash memory card, floppy or hard disk or any othermedium capable of storing computer-readable instructions such asfirmware or microcode in at least one ROM or RAM or Programmable ROM(PROM) chips.

Where in the foregoing description, integers or elements are mentionedwhich have known, obvious or foreseeable equivalents, then suchequivalents are herein incorporated as if individually set forth.Reference should be made to the claims for determining the true scope ofthe present disclosure, which should be construed so as to encompass anysuch equivalents. It will also be appreciated by the reader thatintegers or features of the present disclosure that are described aspreferable, advantageous, convenient or the like are optional and do notlimit the scope of the independent claims. Moreover, it is to beunderstood that such optional integers or features, whilst of possiblebenefit in some embodiments of the present disclosure, may not bedesirable, and may therefore be absent, in other embodiments.

1. A vacuum cleaner comprising: a vacuum motor; one or more time offlight sensors configured to generate first sensor signals dependent onthe proximity of an object to the one or more time of flight sensors; acapacitive sensor located in proximity to a handle of the vacuum cleanerand configured to generate second sensor signals dependent on whether auser is gripping the handle; and a controller configured to: process thegenerated first and second sensor signals to determine whether thevacuum cleaner is actively being used by the user; and in response todetermining that the vacuum cleaner is actively being used, activate thevacuum motor.
 2. The vacuum cleaner of claim 1, wherein the controlleris further configured to deactivate the vacuum motor in response todetermining that the vacuum cleaner is no longer actively being used bythe user.
 3. The vacuum cleaner of claim 1, wherein the controller isconfigured to process the first and second sensor signals to determinewhether the vacuum cleaner is actively being used both when the vacuummotor is activated and when the vacuum motor is deactivated.
 4. Thevacuum cleaner of claim 1, wherein the one or more time of flightsensors comprise a radar device and/or a laser device.
 5. The vacuumcleaner of claim 1, wherein determining that the vacuum cleaner isactively being used comprises determining, from the first sensorsignals, that the object is within a predetermined threshold distancefrom at least one of the one or more time of flight sensors.
 6. Thevacuum cleaner of claim 5, further comprising one or more detachabletools, wherein the predetermined threshold distance is dependent on thetype of detachable tool attached to the vacuum cleaner.
 7. The vacuumcleaner of claim 6, wherein each of the one or more detachable toolscomprises one of the one or more time of flight sensors.
 8. The vacuumcleaner of claim 6, wherein the one or more detachable tools compriseone or more of: a crevice tool; a dusting brush; and a miniaturemotorized tool.
 9. The vacuum cleaner of claim 1, further comprising adetachable wand, wherein the detachable wand comprises one of the one ormore time of flight sensors.
 10. The vacuum cleaner of claim 1, whereinone of the one or more time of flight sensors is located on a main bodyof the vacuum cleaner.
 11. The vacuum cleaner of claim 1, whereindetermining that the vacuum cleaner is actively being used comprisesdetermining, from the second sensor signals, that the user is grippingthe handle of the vacuum cleaner.
 12. The vacuum cleaner of any claim 1,wherein the controller is configured to process the sensor signals byperforming a pre-processing step and a classification step.
 13. Thevacuum cleaner of claim 12, wherein the pre-processing step comprisesextracting features from time portions of the sensor signals.
 14. Thevacuum cleaner of claim 12, wherein the pre-processing step comprisesfiltering the sensor signals.
 15. The vacuum cleaner of claim 13,wherein the classification step comprises processing the extractedfeatures using a machine learning classifier.
 16. The vacuum cleaner ofclaim 15, wherein the machine learning classifier comprises one or moreof: an artificial neural network, a random forest and a support-vectormachine.
 17. A method of operating a vacuum cleaner comprising:generating first sensor signals by one or more time of flight sensors,the first sensor signals dependent on the proximity of an object to theone or more time of flight sensors; generating second sensor signals bya capacitive sensor located in proximity to a handle of the vacuumcleaner, the second sensor signals dependent on whether a user grippingthe handle; processing the first and second sensor signals to determinewhether the vacuum cleaner is actively being used by the user; and inresponse to determining that the vacuum cleaner is actively being used,activating a vacuum motor of the vacuum cleaner.
 18. A computer programcomprising a set of instructions, which, when executed by a computeriseddevice, cause the computerised device to perform a method of operating avacuum cleaner, the method comprising: generating first sensor signalsby one or more time of flight sensors, the first sensor signalsdependent on the proximity of an object to the one or more time offlight sensors; generating second sensor signals by a capacitive sensorlocated in proximity to a handle of the vacuum cleaner, the secondsensor signals dependent on whether a user gripping the handle;processing the first and second sensor signals to determine whether thevacuum cleaner is actively being used by the user; and in response todetermining that the vacuum cleaner is actively being used, activating avacuum motor of the vacuum cleaner.